/**
 * @typedef {object} Phaser.Types.Input.Keyboard.CursorKeys
 * @since 3.0.0
 * 
 * @property {Phaser.Input.Keyboard.Key} [up] - A Key object mapping to the UP arrow key.
 * @property {Phaser.Input.Keyboard.Key} [down] - A Key object mapping to the DOWN arrow key.
 * @property {Phaser.Input.Keyboard.Key} [left] - A Key object mapping to the LEFT arrow key.
 * @property {Phaser.Input.Keyboard.Key} [right] - A Key object mapping to the RIGHT arrow key.
 * @property {Phaser.Input.Keyboard.Key} [space] - A Key object mapping to the SPACE BAR key.
 * @property {Phaser.Input.Keyboard.Key} [shift] - A Key object mapping to the SHIFT key.
 */
